Combine cilantro, olive oil, garlic, red wine vinegar, jalapeno, salt, black pepper, and red pepper flakes in a food processor. Pulse chimichurri sauce until well blended.
Combine water and apple cider vinegar in a small saucepan over medium-high heat until bubbles form at the bottom of the pot but not yet simmering, about 140 degrees F (60 degrees C). Crack egg into a bowl carefully without breaking yolk. Slide egg into water and set a timer for 4 minutes.
Place spinach, bacon, feta cheese, mushroom, sunflower seeds, and red onion on a serving plate. Carefully scoop poached egg from the water using a slotted spoon and place on a paper towel-lined plate to absorb any extra m moisture. Transfer egg to the salad and top with desired amount of chimichurri sauce. Season with salt and pepper.
